krazymatt

I got this 07 Civic Auto EX Coupe back in April used with 8k miles. The first tank with me it averaged 33mpg. Then after I changed the oil and started doing my normal 30 mile one way commute with the car to work I averaged 34mpg 90% of the time. I've gotten up to 36, but always ended up at about 34 mpg on my commute to work which is 70% highway, 30% city/rural.

My probleem is, for that last 3-4 tanks, I've averaged like 29-31mpg. The car has 17k miles now. I even took the car in for an alignment and that didn't change a thing even though it was slightly off. There's no engine lights, but I have noticed a slight decline in power it seems. Any ideas why I would lose 5mpg overnight like that?

My next plan is to visit the dealer, but I already know that song and dance. Usually if there is no engine lights on or such on the dash, then it means they are going to tell me "sorry sir, we couldn't find anything wrong."--and I waste my precious time yet again on the dealer service department. In my experience with dealer service departments is; if it doesn't knock them on the head they won't find it. In other words the car has to have a light on, or plain old not start and run. If I had a dollar for every service advisor that told me they couldn't "reproduce the problem," I'd a paid off a car by now.

Any ideas and input would be greatly appreciated. Thanks in advance...

I love the car otherwise, but for 29-30mpg, I could have a 4cyl Accord and have more room.

Tragedy

iTrader: (10)

I have a faulty fuel sender in my car that causes my gas guage to read inaccurate fuel levels. It is in the 1/4 tank margin.

If this is not your issue, try checking the o2 sensors and other little stuff first before having the dealership mess with it. Good luck.

krazymatt

My gas guage is fine. It's just when I hand calculate my gas mileage is where the problem is. I'm lucky to get 300 miles per tank as where I've gotten upwards of 400 in the past.

I'm wondering about the fuel filter. Would that cause poor mileage?

Also I usually tank up at Sams Club. Is Sams Club gas bad quality? Could it be the gas causing poor mileage? I was thinking of trying Chevron or something for a couple tanks to see.

Wouldn't o2 sensors and such cause a light in the dash to come on?

Tragedy

iTrader: (10)

lol I was half awake when I posted. Just noticed you drive a 2007, sorry dude.

HonCiv02

other things i would consider are air conditioning usage and any changes in how you drive it (hard accelerating, hard stopping, driving above 70-75 mph on the highway). there are a lot of things that contribute to fuel economy that could be affecting it. just my .02 and some things to consider.

krazymatt

That's the thing, is that the car sees the same drive and driver; day in and day out. Not much has changed as far as A/C use either. Matter of fact I was still getting around 35 in early August-Late July, definitely A/C weather.
The Air Filter is a brand new K & N.

The next thing is the fuel filter. Does anyone know where the fuel filter is on this car? Thanks...

rocksinger

Try this put an egg between the accelerator pedal and your foot. It worked for me. Cheap gas like ARCO here in the west has lots of alcohol in it that seems to evaporate long before your engine gets to use it. Hence poor gas milage.

Tiznonay

hmmm, Ive got an 06 LX, and I've noticed that I get a couple more MPG with Chevron than I do with any other gas. If thats not the problem, than its probably the way you're driving. Last summer I was getting like 25 mpg around town with the AC on constantly. This summer im getting over 30, all cuz I stopped driving fast. Its amazing what our engines are capable of when you drive em like a grandma.

plastics

It may be that the stations around your area has started to pump "winter gas".

In the winter, they use a different gas formulation to control smog, but it also results in lower mileage.

Plastics

krazymatt

Thanks for the input guys. I'm currently running a tank of Shell and I plan to try Chevron next and see if it makes any difference. I loved my car initially, but man little things like the gas mileage change has me ticked off right now. Another off topic thing which is annoying is the wiper replacement. I can't find the wipers anywhere and I understand they are super difficult to replace according to other people on this forum. I'm thinking of trading already, but for what? Is there a better car for commuting than a Honda?

ericsd

I use to get like 34 mpg then it fell below 30 mpg, I really think it's the gas quality. Sam's gas is lower quality

Honda civic 06 ex auto

krazymatt

Well I haven't yet calculated the MPG with the Shell gas, but so far I'm at about 310 miles and I still have quarter tank. Before I was looking for a gas station at 300 miles so I do see a big difference with the Shell. I'll see if Chevron does the same. That Sam's Club Gas is full of water or alcohol--who knows maybe even ****!

gearbox

iTrader: (95)

i got 10mpg more mileage just by accelerating slowly and keeping rpm below 3k. this is easy at sea level but hard in hilly areas.

gn3ric

Hello everyone,

I am also getting weird gas mileage with my car. It's a 2007 Sedan Auto Ex and ever since i got the car gas mileage sucked. Even after break in period, i average like 29-30 and on a whole tank i only get like 310-320 and the light comes on. Oh and i do not drive like a speed racer mostly calm although, in my area there are many freeways and locals. Most of my traveling happens on both local and freeway. I'm at 17k miles now and recently a week and half ago i did an oil change. Ever since i got the car my brother told me to use 5w-30 and now I decided to go with what was recommended by the cap and dealer 5w-20. Been running with the new oil for about 2 weeks and a half and still came out to be the same crap. Any body out there with 07 Sedan auto ex been getting something like this? Or is it that LX gets better gas mileage because of no moon roof, rims, etc. One last thing, I found this site where a guy has an LX Auto and has 45k miles on it and he gets really good mpg on it. He posted some pics of his gas mileage and oil change. check it out
http://www.honda-tech.com/zerothread/2368382

someone explain ?

gearbox

iTrader: (95)

alot of people arent too happy with the newer civics mileage. not sure if its only some cars, but ive heard that even some newer hybrids were only getting 26 mpg. but most of it comes down to where you live and how you drive. that link you posted is not that impressive either, thats what most civics from 0 yrs ago were still getting. full synthetic isnt the best idea either. i used to get 32-34 mpg in illinois (sea level, flat roads) using regular dino oil in my 02 civic with mods.

gn3ric

Something wrong with my civic then but that's weird.. i'm so confused..

BJanzen

iTrader: (2)

Did the gas mileage go down when you got the K&N filter? They let in alot more air then the OEM Filters do. More air let in = more gas used. Just a thought. Dont know how you lose power in that scenario.

gearbox

iTrader: (95)

most of the time, the stock airbox can provide more than enough air for the engine. and when you replace it with a short ram, it draws hotter air from the bay, and the pipe itself gets hotter and warms air to some degree. hotter air = less oxygen = ecu adding less fuel to obtain correct a/f mix. thats why you get such terrible mileage in the winter but the car feels more powerful. but again it depends on how you drive. driving a full tank below 3k rpms got me 34mpg. driving below 4k rpms gave me 22 mpg. and driving the car hard above 5k rpm got me 15mpg. driving constant highway usually gets me around 40mpg. again, if you keep your car in good shape, it all comes down to driving habits. when my car was stock, i could barely get 36-38 mpg on the highway. with i/h/e mods, i get 40+ mpg on highway. just think of it this way. the more you press the accelerator, the more gas gets used.

krazymatt

I got my car used with 8k miles this past May. The day I got it; I changed the oil because it looked dirty and replaced the air filter with a K&N because it was filthy. The 34-36mpg I got was after that--then the decline was just recently within the last month. Matter of fact we took it on a road trip to Vegas 600+ miles one way in June and it was getting 32-33mpg and I was running it 75-85. I did notice sporatic changes in gas mileage using Sams Club gas. I even got like 43 mpg on one tank all of the sudden on the same commute to work. I couldn't understand it. I still can't I guess. I have a strong feeling the gas and all the additives they put in it make the world of difference. At times the additives might not be mixed right and you get into the good part of the storage tanks or the bad part. I have a feeling Sams and Costco do cut the gas with stuff in order to be able to sell it 15-30 cents cheaper. This stuff either evaporates or just burns inefficiently.

gearbox

iTrader: (95)

get the stuff in my sig it will make any gas good

swett2k6

i have a 06 civic coupe thats killing me with gas mileage. i did an oil change i put castrol 10 30, i then full my tank then gas light came on after 189 miles. it recommends 5w 20. can oil make a big diff in gas mileage? there's no check light on. i did a diagnostic tes and everything is perfect they say

krazymatt

I would stick to 5w20. I'm not sure if the 10w30 would make that much of a difference, but it is somewhat thicker and it has to affect it some. 189 miles and the fuel light came on???!!! That's pretty bad for a Civic! It seems like mine is doing better, I'll fill up today and find out if it surpassed the 31mpg. It might, I have like over 325 miles and it still has about 1/4 tank. It seems to be doing slightly better every tank of Shell gas instead of Sams. I think I'll get a fuel injector cleaner. Sometimes when it's idling cold it's a little rough.

krazymatt

Okay, Finally tanked up and I calculated just under 32mpg. I'll admit I had been pushing the car to and from work on the hills. About half this last tank I slowed down. A sherriff clocked me 80 on a 65 a few days backso I did slow down--especially after he just gave me a verbal break! If that's not a sign I don't know what is! So from here on out I'm really trying to make it a point to slow down at least 10mph and try to keep the RPM's 3k and below. Hopefully in another month or so when I change the oil and throw in a fuel injector cleaner I can get it back to at least 34 mpg.

swett2k6

well i did my oil change today. gonna full up when i'm goin to work tomorro with shell so i'll see the results. one more thing. here in jamaica we only have 87 and 90. the dealer told mi to use 87.

krazymatt

Swet2k6, Wow! I hadn't noticed you're in Jamaica! I'm envious! I can already see those turquoise-blue waters! I would think it would be easier for you to get a little better mpg's than me being that you're at sea level. I'm at 6k to 7k above sea level with a few steep hills I have to negoitiate every day on my commute to work.

gearbox

iTrader: (95)

32 mpg is pretty good actually. and yeah stick with 87

swett2k6

i need to lower my car. what springs or coil overs u recommend. i want it to be low as a snakes belly

gn3ric

goood stuff matt. I'm gonna be filling up pretty soon probably in a day or two before Monday. I'm gonna go for Cheveron 87 octane. I've been using Costco gas for quite a while now. I wanna see if it makes a difference. I'm gonna try to dedicate myself to driving below 3k and grandma it and see what happens. The thing is.. sometimes you have to push it a bit over 3k cause passing people on freeway with civic is not fun

take it easy.

mdawg

iTrader: (1)

Im driving an older civic but Shell seems to result in the best mpg for me. I avg 31 on my daily commute to and back but im normally doing 75-80 the way there. I live in the a very mountainous region so my city is around 28. Funny how my Y7 with 109 hp gets worse mpg than some of the turbo'd people on here.

gn3ric

Ok guys, I did what most people would recommend by keeping it below 3k rpm and i got the car to shift mostly at 2.5k. I pumped on 9/28 and just pumped today 10/7. On 9/28(Sunday) i pumped 10.33 gal when i had 1 bar left with the light on and today(10/7) i pumped 10.44gal with no bars left :X. I calculated and i only got 30mpg or 30.5559 etc if you want to get complicated. I mostly go to school and on average i travel 30miles a day or sometimes 40 depending if i have errands or not. So... what do you guys think? Is this bad or bad... ii read on some other forum that our tanks carry 13.2 gal? true or not? I pumped today with no bars left and light on and did NOT top off and let the pump stop on its own at 10.44 gal (FULL) So my tank lasted me 1week and 2 days traveling everyday.